Half of the villagers of a certain village have their own houses. One-fifth of the villagers cultivate paddy. One-third of the villagers are literate. Four-fifth of the villagers are under 25 years of age. Which one of the following statements is certainly correct?

50% of the villagers have their own house.
20% of the villagers cultivate paddy.
33.33% of the villagers are literate.
80% of the villagers are under 25 years of age.

Now, as 80% of the villagers are under 25 years of age, and 33.33% of the villagers are literate, so at least some of the villagers under 25 years of age must be literate.